[PATCH RFC net-next 08/12] net: mtk_eth_soc: add fixme comment for state->speed use
Russell King (Oracle)
rmk+kernel at armlinux.org.uk
Wed Apr 6 07:35:35 PDT 2022
Add a fixme comment for the last remaining incorrect usage of
state->speed in the mac_config() method, which is strangely in a code
path which is only run when the PHY interface mode changes.
This means if we are in RGMII mode, changes in state->speed will not
cause the INTF_MODE, TRGMII_RCK_CTRL and TRGMII_TCK_CTRL registers to
be set according to the speed, nor will the TRGPLL clock be set to the
correct value.
Signed-off-by: Russell King (Oracle) <rmk+kernel at armlinux.org.uk>
---
drivers/net/ethernet/mediatek/mtk_eth_soc.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
index a16f02ed921a..b605a823dcd4 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
@@ -324,6 +324,14 @@ static void mtk_mac_config(struct phylink_config *config, unsigned int mode,
state->interface))
goto err_phy;
} else {
+ /* FIXME: this is incorrect. Not only does it
+ * use state->speed (which is not guaranteed
+ * to be correct) but it also makes use of it
+ * in a code path that will only be reachable
+ * when the PHY interface mode changes, not
+ * when the speed changes. Consequently, RGMII
+ * is probably broken.
+ */
mtk_gmac0_rgmii_adjust(mac->hw,
state->interface,
state->speed);
--
2.30.2
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